I'm well aware the new buffed yamato quest (Imposing Iron Assault) isn't until next week but Zig's shop inventory doesn't reflect the aether fuse items that will drop (since I assume you would have to do maintenance or at least restart the server to actually update said shop).
I feel like we aren't going to get said shop since the aether fuses upgrade both Old-type and New-type weapons would be upgraded in it. >.<
Devs seem to avoid editing shops which makes me think the above -see casino shop until episode 4-. x.x